Delivery systems and methods for transcatheter prosthetic valves

ABSTRACT

This invention relates to a delivery apparatus and method for deployment of a mitral valve replacement.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/477,715, filed Apr. 3, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/418,130, filed Jan. 29, 2015, which is a 371national stage application of International Application No.PCT/US2012/050740, filed Aug. 14, 2012, which claims priority to and thebenefit of U.S. Provisional Application No. 61/677,329, filed Jul. 30,2012. Each of these disclosures is incorporated herein by reference inits entirety.

BACKGROUND 1. Field of the Invention

This invention relates to improved delivery devices and methods fordelivering transcatheter prosthetic valves, and particularly to deviceand methods for delivering expandable prosthetic heart valves.

2. Background of the Invention

Cardiac interventionalists are now able to perform complex surgicalprocedures without the need for a full surgical team and operating roomstaff thanks to endoscopic methods and devices developed over the lastfew decades. Cardiac surgeons have now become in some instancestechnicians relied upon only when the traditional cutting and sewingtechniques are necessary. Cardiac catheterization labs and outpatientprocedures are now commonplace and patients are familiar with theconcept that tools, cameras, stents, valves, and other items may beinserted via endoscopic methods into a patient for treatment ordiagnosis.

There are many ways of endoscopically accessing a heart for treatment.Using a modified Seldinger technique of using a sheathed puncturingdevice to access an artery and leaving the sheath in place as a lumendown which catheters and other interventional tools may be deployed,cardiac interventionalists have been able to access the heart in anoff-pump manner. Traditional procedures involve accessing via thefemoral artery, but also known are procedures for accessing the heart ina retrograde manner through the aortic arch or in an antegrade mannerthrough the right atrium and making a transeptal cut. These techniqueshave been used successfully for the deployment of various stents,valves, and various surgical appliances such as annular rings and soforth, as well for delivery of radiologic agents and medicines. It isworth noting that none of these procedures are particularly easy toperform and there are striking differences between the various uses. Forinstance, using a balloon to expand a coated metal stent scaffold in aclogged coronary artery, is very different from using multiple cathetertools to deliver and stitch a new prosthetic valve into the interior ofa diseased heart. There are differences in planning, imaging e.g.echocardiography, differences in tools, length of procedure, risk ofcomplication, types of patients, pathologies that are treatable, and soforth.

Prosthetic heart valves pose particular challenges for delivery anddeployment. Valvular heart disease and specifically aortic and mitralvalve disease is a significant health issue in the US. Annuallyapproximately 90,000 valve replacements are conducted in the US.Traditional valve replacement surgery, the orthotopic replacement of aheart valve, is an “open heart” surgical procedure. Briefly, theprocedure necessitates surgical opening of the thorax, the initiation ofextra-corporeal circulation with a heart-lung machine, stopping andopening the heart, excision and replacement of the diseased valve, andre-starting of the heart. While valve replacement surgery typicallycarries a 1-4% mortality risk in otherwise healthy persons, asignificantly higher morbidity is associated to the procedure largelydue to the necessity for extra-corporeal circulation. Further, openheart surgery is often poorly tolerated in elderly patients.

Thus if the extra-corporeal component of the procedure could beeliminated, morbidities and cost of valve replacement therapies would besignificantly reduced.

While replacement of the aortic valve in a transcatheter manner is thesubject of intense investigation, lesser attention has been focused onthe mitral valve. This is in part reflective of the greater level ofcomplexity associated to the native mitral valve apparatus and thus agreater level of difficulty with regards to inserting and anchoring thereplacement prosthesis.

Several designs for catheter-deployed (transcatheter) aortic valvereplacement are under various stages of development. The Edwards SAPIENtranscatheter heart valve is currently undergoing clinical trial inpatients with calcific aortic valve disease who are considered high-riskfor conventional open-heart valve surgery. This valve is deployable viaa retrograde transarterial (transfemoral) approach or an antegradetransapical (transventricular) approach. A key aspect of the EdwardsSAPIEN and other transcatheter aortic valve replacement designs is theirdependence on lateral fixation (e.g. tines) that engages the valvetissues as the primary anchoring mechanism. Such a design basicallyrelies on circumferential friction around the valve housing or stent toprevent dislodgement during the cardiac cycle. This anchoring mechanismis facilitated by, and may somewhat depend on, a calcified aortic valveannulus. This design also requires that the valve housing or stent havea certain degree of rigidity.

At least one transcatheter mitral valve design is currently indevelopment. The Endovalve uses a folding tripod-like design thatdelivers a tri-leaflet bioprosthetic valve. It is designed to bedeployed from a minimally invasive transatrial approach, and couldeventually be adapted to a transvenous atrial septotomy delivery. Thisdesign uses “proprietary gripping features” designed to engage the valveannulus and leaflets tissues. Thus the anchoring mechanism of thisdevice is essentially equivalent to that used by transcatheter aorticvalve replacement designs.

Accordingly, there still remains a need for improved delivery devicesand methods for transcatheter mitral valve replacements.

BRIEF SUMMARY OF THE INVENTION

Accordingly, in one preferred embodiment, there is provided a deliveryapparatus for a transcatheter valve replacement, comprising a handlehaving an actuator and an actuator spring, a tensioning unit mounted forreciprocal motion responsive to the operation of the actuator, atraveller strap removably mounted within a strap mount of the tensioningunit, a catheter removably held by a catheter mount connected to adistal end of the traveller strap, a pusher unit having a distal endthat is partially disposed within said catheter, and a proximal end thatengages a pusher mount on the handle.

In another preferred embodiment, the traveller strap is plastic ormetal.

In another preferred embodiment, the traveller strap engages thetensioning unit using a friction mount.

In another preferred embodiment, the traveller strap has a plurality ofteeth thereon and engages the tensioning unit via a pawl to constitute aratchet component.

In another preferred embodiment, the pusher unit is about 12 to about 38cm in length.

In another preferred embodiment, the pusher unit is about 60 to about150 cm in length.

In another preferred embodiment, the catheter contains a mitral valvereplacement prosthesis.

In another preferred embodiment, the pusher unit is a hollow tube forcarrying valve anchoring tethers attached to the mitral valvereplacement prosthesis.

In another preferred embodiment, there is provided a method ofdelivering a transcatheter mitral valve replacement to the mitralannulus of a heart, comprising deploying into the mitral annulus atranscatheter mitral valve prosthesis using the delivery apparatus ofclaim 1, wherein the transcatheter mitral valve prosthesis is made froman expandable metal stent body having valve leaflets disposed therein,said stent body covered with a synthetic material or stabilizedpericardial tissue, said the valve leaflets made from stabilizedpericardial tissue, said expandable metal stent body having an optionalatrial cuff, said cuff optionally having a covering made from asynthetic material or stabilized pericardial tissue, said transcathetermitral valve prosthesis deployed via catheter in a compressed state andexpanding upon ejection from the catheter.

In another preferred embodiment, there is provided a method of improvingthe deployment of a mitral valve replacement in a patient, comprisingthe step of fastening one or more tethers to a tether anchor of a mitralvalve prosthesis that is deployed within the mitral annulus, wherein themitral valve prosthesis is made from an expandable metal stent bodyhaving valve leaflets disposed therein, said stent body covered with asynthetic material or stabilized pericardial tissue, said the valveleaflets made from stabilized pericardial tissue, said expandable metalstent body having an optional atrial cuff, said cuff optionally having acovering made from a synthetic material or stabilized pericardialtissue, wherein a distal end of the one or more tethers is anchored inthe left ventricle, wherein the one or more tethers are pre-threadedthrough the expandable metal stent body, and wherein the one or moretethers are tightened by a catheter tool positioned in the left atriumthat pulls the atrially located proximal end of the one or more tethersjust prior to the step of fastening the one or more tethers to create afixed length.

In another preferred embodiment, there is provided a method of deployinga prosthetic valve replacement in a patient, comprising the steps of:

(i) accessing the left ventricle with a catheter using a transvenousapproach;

(ii) anchoring a distal end of at least one tether to the septal wallbetween the right ventricle and the left ventricle;

(iii) withdrawing the catheter from the left ventricle into the leftatrium wherein the action of withdrawing the catheter having at leastone tether disposed therein that is anchored unsheaths a valveprosthesis that was compressed into the catheter and was advanced withinthe catheter to the left atrium, wherein the valve prosthesis is madefrom an expandable metal stent body having valve leaflets disposedtherein, said stent body covered with a synthetic material or stabilizedpericardial tissue, said the valve leaflets made from stabilizedpericardial tissue, said expandable metal stent body having an optionalatrial cuff, said cuff optionally having a covering made from asynthetic material or stabilized pericardial tissue;

(iv) positioning the unsheathed valve prosthesis for deployment into thevalve annulus;

(v) tightening the at least one tether using a catheter tool positionedin the left atrium and pulling the atrially located proximal end of theat least one tether; and

(vi) fastening the at least one tether to a tether anchor of the valveprosthesis that is deployed within the annulus to create a fixed lengthfor the at least one tether, wherein a distal end of the at least onetether is anchored in the left ventricle, wherein the at least onetether is pre-threaded through the expandable metal stent body.

In a more preferred embodiment, the delivery method of the precedingparagraph wherein the prosthetic valve is a mitral valve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a component view of one embodiment of the present invention.

FIG. 2 is an integrated device view of one embodiment of the presentinvention.

FIGS. 3-8 are a series of illustrations showing one example of how amitral valve replacement can be deployed using the delivery apparatus ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

Deployment within the Valvular Annulus

The prosthetic heart valve is, in one embodiment, apically deliveredthrough the apex of the left ventricle of the heart using the deliveryapparatus described herein. In one aspect of the apical delivery, thecatheter delivery system accesses the heart and pericardial space byintercostal delivery. In this case, the pusher unit may be short, e.g.12-38 cm.

In another delivery approach, the catheter delivery system delivers theprosthetic heart valve using either an antegrade or retrograde deliveryapproach using a flexible catheter system, and without requiring therigid tube system commonly used. In another embodiment, the cathetersystem accesses the heart via a trans-septal approach. In either case,where a long distance must be travelled the pusher unit may be 60-150 cmlong.

Tethers

In one preferred embodiment, there are tethers attached to theprosthetic heart valve that are disposed within the lumen of the pusherunit. These tethers anchor to one or more tissue anchor locations withinthe heart. There may be from 1 to 8 tethers which are preferablyattached to the stent.

In another preferred embodiment, the tethers may optionally be attachedto the sealing cuff to provide additional control over position,adjustment, and compliance. In this preferred embodiment, one or moretethers are optionally attached to the sealing cuff, in addition to, oroptionally, in place of, the tethers attached to the stent. By attachingto the sealing cuff and/or the stent, an even higher degree of controlover positioning, adjustment, and compliance is provided to the operatorduring deployment.

During deployment, the operator is able to adjust or customize thetethers to the correct length for a particular patient's anatomy. Thetethers also allow the operator to tighten the sealing cuff onto thetissue around the valvular annulus by pulling the tethers, which createsa leak-free seal.

In another preferred embodiment, the tethers are optionally anchored toother tissue locations depending on the particular application of theprosthetic heart valve. In the case of a mitral valve, or the tricuspidvalve, there are optionally one or more tethers anchored to one or bothpapillary muscles, septum, and/or ventricular wall.

The tethers, in conjunction with the sealing cuff, provide for acompliant valve which has heretofore not been available. The tethers aremade from surgical-grade materials such as biocompatible polymer suturematerial. Examples of such material include ultra high molecular weightpolyethylene (UHWPE), 2-0 exPFTE (polytetrafluoroethylene) or 2-0polypropylene. In one embodiment the tethers are inelastic. It is alsocontemplated that one or more of the tethers may optionally be elasticto provide an even further degree of compliance of the valve during thecardiac cycle. It is also contemplated that the tethers might bebioresorbable/bioabsorbable and thereby provide temporary fixation untilother types of fixation take hold such as biological fibrous adhesionbetween the tissues and prosthesis and/or radial compression from areduction in the degree of heart chamber dilation.

Further, it is contemplated that the prosthetic heart valve mayoptionally be deployed with a combination of installation tethers andpermanent tethers, attached to either the stent or the optional sealingcuff, or both, the installation tethers being removed after the valve issuccessfully deployed. It is also contemplated that combinations ofinelastic and elastic tethers may optionally be used for deployment andto provide structural and positional compliance of the valve during thecardiac cycle.

Stent Structure

Preferably, superelastic metal wire, such as Nitinol™ wire, is used forthe stent, for the inner wire-based leaflet assembly that is disposedwithin the stent, and for the sealing cuff wire form. As stated, it iscontemplated as within the scope of the invention to optionally useother shape memory alloys such as Cu—Zn—Al—Ni alloys, and Cu—Al—Nialloys. It is contemplated that the stent may be constructed as abraided stent or as a laser cut stent. Such stents are available fromany number of commercial manufacturers, such as Pulse Systems. Laser cutstents are preferably made from Nickel-Titanium (Nitinol™), but alsowithout limitation made from stainless steel, cobalt chromium, titanium,and other functionally equivalent metals and alloys, or Pulse Systemsbraided stent that is shape-set by heat treating on a fixture ormandrel.

One key aspect of the stent design is that it be compressible and whenreleased have the stated property that it return to its original(uncompressed) shape. This requirement limits the potential materialselections to metals and plastics that have shape memory properties.With regards to metals, Nitinol™ has been found to be especially usefulsince it can be processed to be austhenitic, martensitic or superelastic. Martensitic and super elastic alloys can be processed todemonstrate the required compression features.

Optional Sealing Cuff

The optional sealing cuff is a substantially flat plate that projectsbeyond the diameter of the tubular stent to form a rim or border. Asused herein, the term cuff, flange, collar, bonnet, apron, or skirtingare considered to be functionally equivalent. When the tubular stent ispulled through the mitral valve aperture, the mitral annulus, by thetether loops in the direction of the left ventricle, the sealing cuffacts as a collar to stop the tubular stent from traveling any furtherthrough the mitral valve aperture. The entire prosthetic valve is heldby longitudinal forces between the sealing cuff which is seated in theleft atrium and mitral annulus, and the ventricular tethers attached tothe left ventricle.

The sealing cuff is formed from a stiff, flexible shape-memory materialsuch as the nickel-titanium alloy material Nitinol™ wire that is coveredby stabilized tissue or other suitable biocompatible or syntheticmaterial. In one embodiment, the sealing cuff wire form is constructedfrom independent loops of wire that create lobes or segments extendingaxially around the circumference of the bend or seam where the sealingcuff transitions to the tubular stent (in an integral sealing cuff) orwhere the sealing cuff is attached to the stent (where they areseparate, but joined components).

Referring now to the FIGURES, FIG. 1 shows in a components view, thedelivery apparatus 110 for a transcatheter mitral valve replacement,comprising a handle 120 having an actuator 130 and an actuator spring140. A tensioning unit 150 is mounted for reciprocal motion responsiveto the operation of the actuator 130. A traveller strap 160 is removablymounted within a strap mount 170 of the tensioning unit 150. A catheter180 is removably held by a catheter mount 190 which is connected to adistal end of the traveller strap 160. A pusher unit 200 has a distalend that is partially disposed within said catheter 180, and a proximalend that engages a pusher mount 210 on the handle 120.

FIG. 2 shows some of the delivery apparatus in a perspective,consolidated view ready to be used.

FIG. 3 shows a ventricular transseptal tether (not shown) beinginstalled using the catheter delivery unit 110 with catheter 180extended, via an atrial transseptal access down through the mitralannulus and piercing the ventricular septum.

FIG. 4 shows catheter delivery system 110 installing a ventriculartransseptal anchoring device 220. Here, this is illustrated as twopledgets 230 sandwiching either side of the ventricular septum withinstallation tether 240 still attached and held by catheter 180.

FIG. 5 shows an over the wire delivery of a mitral valve replacement270, exiting the catheter 180.

FIG. 6 shows the mitral valve replacement 270 delivery of FIG. 5,expanded fully with three stent tethers 250, joined with anintraventricular tether collar 260, and attached to septal anchor 220 byinstallation tether 240. FIG. 6 also shows three (3) tensioning tethers280 extending from catheter 180 and used to establish the proper fit ofthe mitral valve replacement under imaging, e.g. echocardiography.

FIG. 7 shows mitral valve replacement positioned and deployed correctly.

FIG. 8 shows that tensioning tethers (3) may be knotted and clipped, andthe catheter withdrawn.

The references recited herein are incorporated herein in their entirety,particularly as they relate to teaching the level of ordinary skill inthis art and for any disclosure necessary for the commoner understandingof the subject matter of the claimed invention. It will be clear to aperson of ordinary skill in the art that the above embodiments may bealtered or that insubstantial changes may be made without departing fromthe scope of the invention. Accordingly, the scope of the invention isdetermined by the scope of the following claims and their equitableEquivalents.

The invention claimed is:
 1. A method of implanting a prosthetic mitralvalve in a mitral valve annulus of a heart of a patient, the methodcomprising: loading the prosthetic mitral valve into a delivery devicein a collapsed condition; delivering the prosthetic mitral valve to aleft atrium of the patient through an atrial septal wall separating theleft atrium from a right atrium of the heart of the patient; deployingthe prosthetic mitral valve into the mitral valve annulus of the heartof the patient by allowing the prosthetic mitral valve to transitionfrom the collapsed condition to an expanded condition within the mitralvalve annulus; without piercing an exterior wall of the heart, anchoringthe prosthetic mitral valve to a structure of the heart with ananchoring tether; and after deploying the prosthetic mitral valve withinthe mitral valve annulus, adjusting a length of the anchoring tetherbetween the prosthetic mitral valve and the structure of the heart. 2.The method of claim 1, wherein anchoring the prosthetic mitral valve tothe structure of the heart includes attaching a first end of theanchoring tether to the prosthetic mitral valve, and attaching a secondend of the anchoring tether to the structure of the heart.
 3. The methodof claim 2, wherein the first end of the anchoring tether includes aplurality of stent tethers, each of the plurality of stent tether havinga first end coupled to the prosthetic mitral valve and a second endcoupled to a collar.
 4. The method of claim 2, wherein the structure ofthe heart is a papillary muscle of the heart.
 5. The method of claim 2,wherein the structure of the heart is a ventricular septum separating aleft ventricle from a right ventricle of the heart of the patient. 6.The method of claim 5, further comprising: prior to anchoring theanchoring tether to the ventricular septum, inserting the deliverydevice through the mitral valve annulus, through the left ventricle andpiercing the ventricular septum, the delivery device including adelivery sheath defining a lumen and the prosthetic mitral valve beingdisposed within the lumen of the delivery sheath while inserting thedelivery device.
 7. The method of claim 5, wherein the second end of theanchoring tether is attached to the ventricular septum before allowingthe prosthetic mitral valve to transition from the collapsed conditionto the expanded condition within the mitral valve annulus.
 8. The methodof claim 5, further comprising attaching an anchor device to theventricular septum, the anchor device having a first portion abutting afirst side wall of the ventricular septum, and a second portion abuttinga second side wall of the ventricular septum.
 9. The method of claim 8,wherein the first and second portions of the anchor device are pledgets.10. The method of claim 1, wherein the prosthetic mitral valve includesa valve body, the anchoring tether has a first end attached to aventricular end of the valve body, and anchoring the prosthetic mitralvalve to the structure of the heart includes attaching a second end ofthe anchoring tether to the structure of the heart.
 11. The method ofclaim 10, wherein the prosthetic mitral valve includes an atrial cuffextending from an atrial end of the valve body.
 12. The method of claim11, wherein allowing the prosthetic mitral valve to transition from thecollapsed condition to an expanded condition within the mitral valveannulus includes engaging the atrial cuff to an atrial side of themitral valve annulus.
 13. The method of claim 12, wherein allowing theprosthetic mitral valve to transition from the collapsed condition to anexpanded condition includes removing a delivery sheath from the valvebody.
 14. The method of claim 1, further comprising urging at least aportion of the prosthetic mitral valve body against the mitral valveannulus.
 15. The method of claim 1, wherein the anchoring tether isbioabsorbable.
 16. The method of claim 1, wherein the anchoring tetheris elastic.
 17. The method of claim 1, wherein the anchoring tether isinelastic.
 18. The method of claim 1, wherein the anchoring tether is abiocompatible polymer suture.
 19. The method of claim 1, wherein theanchoring tether is formed of a material selected from the groupconsisting of ultra-high molecular weight polyethylene,polytetrafluoroethylene, and polypropylene.